s3c tipped us to an infrared remote extender at Electronics Lab. A 555 timer IC is set to oscillate at 38kHz. Each IR pulse from a remote control, detected by a TSOP1738 IR receiver module, activates the timer. The timer blinks several IR LEDs through a transistor at 38kHz, recreating the input signal. Handy little device with no programming required.

Thanks for the tip!

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i did it sir, but i got failure result. i am using solderless bread board and only once the red led flicker. then it off.how can i check above the circuit working correctly…. any tips for check circuit working correctly? please help. i read above the link TEST tag. i didnt result.

Well it’s a very simple circuit, so you should first check that all the simple stuff, like checking your connections are correct and that you have the components the correct way around, the correct values and connected to the correct places. Don’t assume they are correct, actually check over them carefully, as these are the most common problems for beginners. Also make sure your battery is good! It would help if you had an Oscilloscope, but a Multimeter would be better than nothing.

If you short Q1 from Collector to Emitter (the two outside legs) for a moment, when you release it, the LED should flash for a second. If it doesn’t then your problem is from there onwards to the right of the circuit.

I wouldn’t think a 9V battery (or any battery) would last long operating an NE555, it might last OK if used with one of the CMOS versions, but if you are looking to use it longer term you’d be better off using a plugpack or similar.

Anyway – this is not really the place to be discussing this stuff, so if you need anything further it’s best you start up a thread in the Forum.

Actually, it looks like Q1 is holding the 555 off, so if you just remove Q1 from the breadboard, the LED should start flashing (it may appear on all the time depending on the timing). I wouldn’t say it’s the best circuit I’ve seen.